#define _CRT_SECURE_NO_WARNINGS 1

#include <iostream>
#include <set>

int main()
{
	std::set<int> gather;

	std::pair<std::set<int>::iterator, bool> is_insert;

	is_insert = gather.insert(0);
	is_insert = gather.insert(1);
	is_insert = gather.insert(2);
	is_insert = gather.insert(3);

	std::set<int>::iterator it = gather.begin();
	while (it != gather.end())
	{
		std::cout << *it << std::endl;
		++it;
	}

	return 0;
}